The irradiation effects of low energy proton on both Direct Current (DC) and the Radio Frequency (RF) performance of InGaP/GaAs single heterojunction bipolar transistors (SHBTs) are investigated with fluence up to 5 x 10(12) protons/cm(2). The current gain in RF and the cutoff frequency (f(T)) show a little degradation even at proton fluence of 5 x 10(12)/cm(2). The open-collector technique is used to extract the access resistances. Meanwhile 10 MeV proton irradiation is also investigated in order to compare the differences induced by different proton energies. The results indicate that InGaP/GaAs HBT is tolerant to proton irradiation. (C) 2014 Elsevier Ltd. All rights reserved.